Given the favorable effects of calcitriol on chemotherapy toxicity noted in the ASCENT-1 trial [14] (not confirmed in ASCENT II, but the different docetaxel dosing in the arms makes this comparison less clear), and the effect in vitro on VDR expressing melanoma cell lines, we hypothesized that the combination of calcitriol plus temozolomide might result in enhanced response rates and a more tolerable side effect profile. Here, VDR is linked to melanoma.